Ok, so in the comics based on the TV show "Batman: The Animated Series", Pamela Isley had green skin due to her high exposer to the chemicals she uses. I was wondering, when does she get her green skin (in the animated universe, mind you)? Did she ever have green skin on the TV show or was this just in the comics?

during batman: the animated series, poison ivy looked like a human ( with normal skin) who just had a plant fixation. In the reboot, the new batman adventures/ gotham knights, she had really pale skin. so it was just in the comics they made her skin green. there has been no animated shows that have her with green skin, unfortunately.

When the time came to redesign the characters for the WB series, the creators felt that the original Pamela Isley was a bit too fit, too much the vision of health.  The design was great, and I loved how she looked, but they decided to make her more nymph-like.  There was no particular point in time or event that gave her the unique hue.  When the new episodes started broadcasting on WB (now CW) she just had the new look with no explanation other than a design choice.

It might be a side effect of her "mutation" 

"  there has been no animated shows that have her with green skin, unfortunately. "